Santutxu is a neighbourhood of the Spanish city of Bilbao. It belongs to the 4th urban district, named Begoña. It is a popular residential neighbourhood which has a significant number of small businesses and has received some waves of immigration in the last years, particularly Romanians. The Begoña district consists of three neighbourhoods: Santutxu, Begoña and Bolueta.
According to research on population density, and data from the Bilbao City Council, Santutxu has the third most densely populated sq/km in Europe, with about 41.378 residents per sq/km, when considering districts of a certain size coming in third place after L'Hospitalet de Llobregat in Greater Barcelona and La Goutte d’or in Paris, neighbourhoods which have slightly more than 50.000 residents per sq/km. However, there is a popular myth among locals that Santutxu is the most densely populated neighbourhood in Europe.